It's a mental stimulator and great for studying they say.Still looking into it but many use it for school study sessions.

sorry for my foolish brain, is all these "sum" materials like magnesium (the only one i know) etc actually generated by our body or we can get them from food? But since we can't get enough, we need vitamins for supplement?

You need to supplement, some is in food but not enough at all.

Our bodies don't make magnesium, calcium and many others.Some foods have them but not enough.